共查询到20条相似文献，搜索用时 328 毫秒
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植物DNA甲基化是导致转基因沉默的直接和主要因素。甲基化的出现严重制约了植物基因工程的商业化生产。本将对植物DNA甲基化的机制、作用等问题作一综述。 相似文献
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Meng-wen Zhang Xu Che Shu Zheng Lei Zheng 《Journal of Zhejiang University. Science. B》2017,18(5):365-372
The tumor microenvironment (TME) plays an important role in supporting cancer progression. The TME is composed of tumor cells, the surrounding tumor-associated stromal cells, and the extracellular matrix (ECM). Crosstalk between the TME components contributes to tumorigenesis. Recently, one of our studies showed that pancreatic ductal adenocarcinoma (PDAC) cells can induce DNA methylation in cancer-associated fibroblasts (CAFs), thereby modifying tumor-stromal interactions in the TME, and subsequently creating a TME that supports tumor growth. Here we summarize recent studies about how DNA methylation affects tumorigenesis through regulating tumorassociated stromal components including fibroblasts and immune cells. We also discuss the potential for targeting DNA methylation for the treatment of cancers. 相似文献
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DNA甲基化的影响因素及对基因表达的调控 总被引：1，自引：0，他引：1
DNA甲基化是一种由DNA甲基转移酶介导的主要表观遗传修饰方式,是调节基因组功能的重要途径。本文重点综述了影响DNA甲基化的主要因素以及DNA甲基化与基因表达调控的关系。 相似文献
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细胞质DNA 总被引：1，自引：0，他引：1
自从 2 0世纪 6 0年代在衣藻的叶绿体中发现有DNA ,在鸡胚肝细胞线粒体中也发现有DNA以后 ,又陆续从各种生物细胞的叶绿体、线粒体和质粒中分离出DNA ,并发现其具有遗传物质的功能 ,人们称其为细胞质DNA。1 细胞质DNA的形态除在某些低等真核生物中有少量线粒体DNA是线状外 ,其它线粒体DNA (mtDNA)和叶绿体DNA(ctDNA)均呈双链环状。细胞质DNA的大小随生物种类不同而不同。动物细胞线粒体基因组比较小 ,而酵母线粒体DNA约是动物DNA的 5倍长 ,植物线粒体DNA的大小又约是酵母线粒体DNA的 5倍长。与核DNA相比 ,线粒体DNA所… 相似文献
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The 2015 Nobel Prize in Chemistry was awarded jointly to Tomas Lindahl, Paul Modrich and Aziz Sancar to honour their accomplishments in the field of DNA repair. Ever since the discovery of DNA structure and their importance in the storage of genetic information, questions about their stability became pertinent. A molecule which is crucial for the development and propagation of an organism must be closely monitored so that the genetic information is not corrupted. Thanks to the pioneering research work of Lindahl, Sancar, Modrich and their colleagues, we now have an holistic awareness of how DNA damage occurs and how the damage is rectified in bacteria as well as in higher organisms including human beings. A comprehensive understanding of DNA repair has proven crucial in the fight against cancer and other debilitating diseases. 相似文献
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This article presents a brief overview of DNA chips, or microarrays. Microarrays are a very significant technological development
in molecular biology, and are perhaps the most efficient tool available for functional genomics today. 相似文献
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DNA分类方法的探讨 总被引：3，自引：0，他引：3
ＤＮＡ序列分类的方法有很多种．本文给出了两种模型都是在图象的基础上，利用图象的直观、易于分析等优点，找到各种碱基不同的特征，得出一个比较合理的方法． 在建立模型时，先计算出给定的前２０种ＤＮＡ序列中各碱基Ａ，Ｇ、Ｃ、Ｔ的含量 （将一串长序列简化成了四个百分含量数值，大大简化了序列），并以此含量为数据作出直角坐标系下的二维曲线．根据曲线的特征，得出了两个算法，一个是以其中的一个ＤＮＡ序列中碱基的含量大于其它三种含量为特征分出类别，对２１至４０种序列的分类正确率达到 ８０％，对于题中所给的 １８２种序列分类正确率为 ４２％；另一个是通过转化曲线为直线的方法找出符合分类特征的区间，根据是否在此区间内而分出类别，对２１至４０种序列的分类正确率达到１００％，对于题中所给的１８２种序列分类正确率为８５％． 最后，通过对比两种模型的结果，判断出两种模型的优劣，并分析了其中的原因． 相似文献
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从检测的原理、局限性和影响因素等方面对几种主要的DNA单链断裂的检测技术包括快速沉降技术、碱性解旋、碱性洗脱和单细胞凝胶电泳进行了综述，重点介绍了单细胞凝胶电泳的产生和发展、检测范围和影响因素，为检测DNA损伤程度提供了依据。 相似文献
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Using the complete genome of Plasmodiumfalciparum 3D7 which has 14 chromosomes as an example, we have examined the distribution functions for the amount of C or G and A or T consecutively and non-overlapping blocks of m bases in this system. The function P(S) about the number of the consecutive C-G or A-T content cluster conforms to the relation P(S)oce-as;values of the scaling exponent αCG are much larger than αAT; and αAT of 14 chromosomes are hardly changed, whereas αCG of 14chromosomes have a number of fluctuations. We found maximum value of A-T cluster size is much larger than C-G, which implies the existence of large A-T cluster. Our study of the width function ξ(m) of cluster C-G content showed that follows good power law ξ(m)ocm-γ. The average γ for 14 chromosomes is 0.931. These investigations provide some insight into the nucleotide clusters of DNA sequences, and help us understand other properties of DNA sequences. 相似文献
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亲子关系诉讼目前呈现上升的趋势,而在解决亲子关系诉讼关键是查明亲子关系真相。DNA在这一过程中发挥着至关重要的作用。但是我国法律并没有对亲子鉴定做直接的规定,更没有对亲子鉴定的程序以及法律效力的规定。在介绍国外有关亲子鉴定的法律法规后,建议借鉴国外立法的基础上完善我国的亲子鉴定方面的法律规定。 相似文献
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改进的CTAB提取植物DNA方法 总被引：27，自引：0，他引：27
根据DNA分子的物理化学特性及植物材料的特点,改进了传统利用十六烷基三甲基溴化铵(CTAB)法提取植物叶片中DNA的操作方法,采用新鲜配制的CTAB溶液、液氮快速研磨植物材料、添加适量还原剂和适量吸取提取液中核酸层等措施,减少了提取过程中提取液的褐变和杂质对DNA产质量的影响.同时,列出了提取过程中各操作步骤的注意事项和关键点.该方法操作简便、快捷,提取出的DNA质量较好,能很好地用于DNA的分子遗传特性分析,可作为教学和研究工作中植物DNA的提取方法. 相似文献
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DNA is the hereditary material in humans and almost all other organisms. It is essential for maintaining accurate transmission of genetic information. In the life cycle, DNA replication, cell division, or genome damage, including that caused by endogenous and exogenous agents, may cause DNA aberrations. Of all forms of DNA damage, DNA double-strand breaks(DSBs) are the most serious. If the repair function is defective, DNA damage may cause gene mutation, genome instability, and cell chromosome loss, which in turn can even lead to tumorigenesis. DNA damage can be repaired through multiple mechanisms. Homologous recombination(HR) and non-homologous end joining(NHEJ) are the two main repair mechanisms for DNA DSBs. Increasing amounts of evidence reveal that protein modifications play an essential role in DNA damage repair.Protein deubiquitination is a vital post-translational modification which removes ubiquitin molecules or polyubiquitinated chains from substrates in order to reverse the ubiquitination reaction. This review discusses the role of deubiquitinating enzymes(DUBs) in repairing DNA DSBs. Exploring the molecular mechanisms of DUB regulation in DSB repair will provide new insights to combat human diseases and develop novel therapeutic approaches. 相似文献